The invention relates to a handling device for feeding and/or removing workpieces as unfinished parts to and/or from machining or assembly equipment for machining and/or assembly purposes and for picking up workpieces as finished parts after machining and/or assembly, having workpiece carriers, on which the workpieces are arranged, workpiece-carrier stack units, which have workpiece carriers arranged one above another, a workpiece handling unit, which removes the workpieces from the respective workpiece carriers and feeds them to the machining and/or assembly equipment and, after machining/assembly, sets them down again on the workpiece carrier, a workpiece-carrier handling unit, which feeds the respective workpiece carriers having unmachined workpieces and belonging to a workpiece-carrier stack unit to the workpiece handling unit, from a pick-up position into a standby position and, after its workpieces have been machined, sets this workpiece carrier down from the standby position into a set-down position of a further workpiece-carrier stack unit, a stack transport unit, which transports the workpiece-carrier stack units within the device in the transport direction, specifically from a feed position to which the workpiece-carrier stack units having the unmachined workpieces are fed from outside, as far as a removal position, from which the workpiece-carrier stack units having the machined workpieces are removed to the outside.
Handling devices of the type mentioned at the beginning are known, and are used for charging machining/assembly machines and the like. In the process, the workpieces are stored on workpiece carriers, fed pallet by pallet, machined and removed again pallet by pallet. In this case, use is generally made of a pallet transfer device having two controlled axes in the horizontal direction and in the vertical direction, to which outside the working area, via a belt, workpiece carriers having unmachined workpieces can be fed, it being possible for workpiece carriers with machined workpieces to be removed from the working area via a further belt. As a rule, the workpiece carriers are transferred to a handling unit which transfers the pallet to a defined machining position. Individual workpieces are accepted from the machining position, for example by means of grippers or other handling units, and fed to the machining equipment. Following machining, the workpieces are in turn deposited on a pallet. These pallets are in turn arranged to form a stack and are removed stack by stack from the device following complete machining.
Devices of this type are relatively complicated, since it is necessary to ensure continuous monitoring of the handling system, which goes counter to a complete automation process.
EP-0 673 711 discloses a handling system in which there is an operating area which is sealed off from the outside by a protective wall and within which a pallet transfer unit is provided in order to provide workpiece carriers with unmachined workpieces and to pick up workpiece carriers following machining. The workpiece carriers are fed into the operating area by means of a rotary table with an H-shaped rotary frame, into which workpiece-carrier stacks can be moved on roller carriages. The rotary table has a protective wall section, by means of which the operating area can be separated off completely from a charging area, so that during the machining of the workpiece carriers within the operating area, the workpiece-carrier stacks can be changed in the loading area without any risk. For the purpose of presentation, the workpiece-carrier stacks must be restacked, which ultimately means that there is a loss in time.
On the basis of the aforementioned prior art, the present invention is based on the object and the technical problem of specifying an improved handling device for feeding workpieces which, with the effect of economic use, makes an increase in automation possible.
In addition, an improved method of handling workpieces is to be specified, which ensures economic use and permits simple implementation in design terms.
The handling device according to the invention is accordingly distinguished by the fact that between the feed position and removal position there is at least one further intermediate position for one workpiece-carrier stack unit in each case, the stack transport unit is constructed such that it can displace at least two workpiece-carrier stack units arranged upstream of the removal position by one position in the transport direction to the removal position, a control device being constructed such that it activates the components in such a way that the workpiece-carrier handling unit removes the workpiece carriers having workpieces to be machined in a pick-up position and, after their workpieces have been machined, sets the workpiece carriers down in a set-down position, i.e. the pick-up position is in particular designed to be adjacent to the set-down position, as soon as there is a completely machined workpiece-carrier stack unit in the removal position, the pick-up and set-down positions of the workpiece-carrier handling unit are displaced by one position in the direction opposite to the transport direction, after the workpiece-carrier stack unit has been removed from the removal position, the workpiece-carrier stack units located upstream of the removal position are displaced at least partly by one position in the transport direction by means of the stack transport unit and, at the same time, the pick-up position and set-down position of the workpiece-carrier handling unit is also displaced by one position in the transport direction and, as a result, a workpiece-carrier stack unit having workpiece carriers with unmachined workpieces can be introduced into the feed position. As a result of the device according to the invention, the necessary restacking of the workpiece-carrier stacks, which is required in the prior art before the workpieces are presented to the machining equipment, is dispensed with, which reduces the downtimes of the machining device and is associated with a beneficial influence on the cycle-time intervals during the machining of the workpieces.
A preferred configuration of the inventive device is distinguished by the fact that between the feed position and the removal position there is a single intermediate position.
A device that can be implemented particularly simply in design terms is distinguished by the fact that the workpiece-carrier handling unit can be displaced about a horizontal and vertical axis, and the transport direction of the stack transport unit is arranged essentially parallel to the horizontal axis of the workpiece-carrier handling unit.
A configuration which is particularly preferred with regard to increased operating safety is distinguished by the fact that there are mobile protecting walls which, when workpiece-carrier stack units are being fed or when workpiece-carrier stack units are being removed, block off the area of the adjacent position, in which machining takes place.
A configuration which is particularly preferred with regard to a simple constructional design of the stack transport unit is distinguished by the fact that the stack transport unit has a linear guide and, between the respective workpiece-carrier stack units, has projecting units that can be pivoted in, a particularly advantageous development being distinguished by the fact that the stack transport unit has a rotary-shaft unit on which there are projecting units which are arranged so that they can be displaced longitudinally by means of an assembly and rotated by means of an assembly.
A further advantageous configuration of the handling device according to the invention is distinguished by the fact that the stack transport unit has a chain drive with assemblies that can be activated, or the stack transport unit has a push-rod drive which can be activated via drive assemblies.
During the machining of workpieces with correspondingly long machining times, that is to say during processes which are not critical in terms of their cycle time, the task of the workpiece-carrier handling unit with respect to the transport can perform the tasks of the stack transport unit, as a result of which the latter can be dispensed with.
The method according to the invention of handling workpieces which are mounted on workpiece carriers, the said workpiece carriers being stacked to form workpiece-carrier stack units, the workpiece-carrier stack units being fed to a feed position from outside, fed in the transport direction by means of a stack transport unit or a workpiece-carrier handling unit to a removal position, the workpiece-carrier handling unit feeding the individual workpiece carriers to a standby position, to which the workpiece handling unit makes access, having the following method steps:
a) feeding a workpiece-carrier stack unit to the feed position from outside,
b) transporting the workpiece-carrier stack unit in the transport direction into an intermediate position,
c) if appropriate, repeating steps a) to c) in accordance with the number of intermediate positions,
d) removing a workpiece carrier by means of the workpiece-carrier handling unit from an intermediate position currently defined as a pick-up position to feed it to a machining position,
e) removing the workpieces and feeding machining/assembly equipment by means of the workpiece handling unit and setting the workpiece down on the workpiece carrier after machining, until the workpieces of the respective workpiece carrier have been machined completely,
f) removing the workpiece carrier from the machining position by means of the workpiece-carrier handling unit and setting it down in the removal position currently defined as the set-down position,
g) repeating steps d) to f) until the workpiece-carrier stack unit in the current pick-up position has been processed completely,
h) displacing the current pick-up and set-down positions in the direction opposite to the transport direction by at least one position and removing the machined workpiece-carrier stack unit from the removal position,
j) displacing the workpiece-carrier stack units arranged upstream of the removal position by one position in the transport direction and simultaneously displacing the pick-up/set-down positions of the workpiece-carrier handling unit by one position in the transport direction,
k) feeding a further workpiece-carrier stack unit into the feed position from outside,
l) repeating method steps d) to j).
A particularly preferred configuration of the method according to the invention is distinguished by the fact that the pick-up position and the set-down position for the stack unit are designed to be adjacent, it being preferable for the offset between the pick-up/set-down positions for the workpiece-carrier handling unit to be preferably one position unit counter to or in the transport direction.
A particularly compact plant is achieved if, according to the invention, a feed position, an intermediate position and a removal position are provided, these positions advantageously being arranged parallel with the horizontal displacement axis of the workpiece-carrier handling unit.
A particularly preferred configuration of the method according to the invention is distinguished by the fact that the workpiece-carrier stack units located upstream of the removal position are displaced by the stack transport unit or workpiece-carrier handling unit in a transport direction (T) which runs parallel to the horizontal axis (H) of the workpiece-carrier handling unit.
There are situations in which the workpiece handling unit initially has to populate the machining equipment with a predefined number of workpieces, in order that the said equipment starts machining. Taking account of this configuration, a preferred configuration of the method of the invention consists in the workpiece handling unit feeding a set of workpieces from a workpiece-carrier unit individually or jointly to the machining equipment, the workpiece-carrier unit which is then emptied being fed to an intermediate storage position, after the processing of all the workpiece-carrier/stack units to be machined, the workpieces still in the machining equipment being fed to the empty workpiece carrier unit. This option is not possible in the known methods, since in this method restacking of the workpiece-carrier stack introduced into the operating area necessarily has to be carried out. With this feature, the method according to the invention assures the correct batch processing of the respective workpiece carriers.
Further embodiments and advantages of the invention emerge from the features further listed in the claims, and from the exemplary embodiments specified below. The features of the claims can be combined with one another in any desired way, provided that they are not obviously mutually exclusive.